Timeline Of Evolution

Brick Bungalow

Brick Bungalow

Total Posts: 4667

Joined 28-05-2009

Sr. Member

Total Posts: 4667

Joined 28-05-2009

Posted: 12 December 2012 07:33

Having read a bit about evolutionary biology I notice a fairly reliable growing consensus about the essential structure of theory. There are disputes of course but the links between species seem to converge with regularity.

One disparity that stands out rather starkly is the timeframes. Sometimes they converge of course but often the spans deemed necessary for specifically identifiable changes vary drastically from one researcher to the next.

I’m curious about how such figures are arrived at in the first place. I know that figures are cross referenced with geology, among other things, to plot whole epochs. But how are estimates for single isolated changes in biology- one species to the next- specifically calculated?

Having read a bit about evolutionary biology I notice a fairly reliable growing consensus about the essential structure of theory. There are disputes of course but the links between species seem to converge with regularity.

One disparity that stands out rather starkly is the timeframes. Sometimes they converge of course but often the spans deemed necessary for specifically identifiable changes vary drastically from one researcher to the next.

I’m curious about how such figures are arrived at in the first place. I know that figures are cross referenced with geology, among other things, to plot whole epochs. But how are estimates for single isolated changes in biology- one species to the next- specifically calculated?

By guess and by golly. Or, magic.

One way of computing timelines for changes involving several genes is to get some sort of estimate of the probability of mutations in the genes and then work it backward (e.g., if one would expect a mutation once in a thousand years then for a single gene mutation estimate that if it’s observed today it occurred at least 1000 years ago, plus or minus a fudge factor).